In the US, fuel taxes are earmarked for road building and repair, but aren't enough to pay for them at either the federal or state level. That completely ignore

In the US, fuel taxes are earmarked for road building and repair, but aren't enough to pay for them at either the federal or state level. That completely ignores the negative externality of carbon emission. Meanwhile, in a few states, cigarette taxes are actually targeted at the negative externality: health problems, including secondary smoke. So I guess it depends on what you want to achieve. Failing to tax a negative externality like carbon emissions would seem to be corrupting influence that misaligns the entire economy.